Prediction-market platforms Kalshi and Polymarket posted a combined $44.8 billion in trading volume in June 2026, a 75% jump from May's $25.66 billion, as the FIFA World Cup fueled a surge in betting activity. Kalshi led the growth, climbing 87.4% to $31.5 billion, while Polymarket's international platform rose 45% to $10.26 billion and its US arm nearly doubled to $3.04 billion.
The tournament, which kicked off June 11, has become the platforms' biggest driver yet: Kalshi's World Cup winner market alone has attracted more than $832 million in bets, with roughly 35% currently favoring France to lift the trophy. Individual match contracts on Polymarket have each drawn $500,000 to $2 million in volume.
The boom comes as prediction markets face mounting legal pressure, with more than a dozen US states accusing Kalshi and Polymarket of offering unlicensed sports betting. Both platforms and the CFTC maintain federal law permits the contracts, setting up a regulatory clash even as trading volumes hit new records.